Monster Beverage Corp.’s energy drinks have been cited in the deaths of five people in the past year, according to incident reports that doctors and companies submit to the U.S. Food and Drug Administration.

The reports said the victims consumed Monster drinks prior to their deaths, Shelly Burgess, an FDA spokeswoman, said today in a phone interview. The FDA said the incidents, which are voluntarily reported, are considered to be allegations, and no conclusion is drawn until an investigation is completed. Shares of Corona, Calif.,-based Monster fell the most since 2008.

The FDA reports are being used by parents in Maryland who sued Monster last week, claiming the drinks led to caffeine toxicity that killed their 14-year-old daughter. Senator Dick Durbin, an Illinois Democrat, is asking the FDA to consider caffeine limits on energy drinks after emergency room visits involving such products jumped 10-fold from 2005 through 2009.

“FDA continues to evaluate the emerging science on a variety of ingredients, including caffeine,” Burgess said in an earlier e-mail.

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The five death reports, and a sixth in 2009, were among 37 adverse reaction reports since 2004 that mentioned Monster drinks, according to a log of incidents that health professionals, companies and the public voluntarily recorded with the FDA. The agency has said it’s working on draft guidelines that would ensure energy drinks are safe.

Monster fell 14 percent to $45.73 at the close of New York trading, erasing all the gains the stock had made this year.

The log of adverse incident reports was given to Bloomberg News by Kevin Goldberg, a lawyer representing the parents of the 14-year-old girl who died. The girl, Anais Fournier, had consumed two Monster drinks, according to a copy of the complaint filed Oct. 17 in state court in Riverside, Calif.

Monster, the largest U.S. energy drink maker by sales volume, sold about $1.6 billion worth of such drinks last year, the majority of company revenue, according to data compiled by Bloomberg. Its energy drink sales have tripled since 2006.

“Over the past 16 years Monster has sold more than 8 billion energy drinks, which have been safely consumed worldwide,” the company said in an e-mailed statement sent through an outside spokesman, Evan Pondel. “Monster does not believe that its beverages are in any way responsible for the death of Ms. Fournier. Monster is unaware of any fatality anywhere that has been caused by its drinks.”

The company said it intends to vigorously defend itself against the lawsuit and won’t comment further.

Emergency room visits involving energy drinks increased to 13,114 in 2009, with about half those trips made by patients 18 to 25 years old and also involving drugs or alcohol, according to a November report by the Substance Abuse and Mental Health Services Administration. The event reports linked to Monster claimed that some of the life-threatening illnesses were characterized by heart attack, chest pain and vomiting.

The Center for Food Safety Adverse Event Reporting System is used by the public to report illnesses that the user deems to be linked to a particular food, drug or dietary supplement. The claims, which serve as a signal to the FDA, don’t prove causation, Burgess said.

Monster and competitors such as Red Bull aren’t bound by the FDA guidelines for caffeine in sodas, because energy drinks are often sold as dietary supplements. Monster doesn’t list the amount of caffeine in its proprietary formula, only that the ingredient along with the plant extract guarana and the amino acid taurine are in the drink, according to the lawsuit.

Soda typically can have as many as 71 milligrams of caffeine per 12 ounces for the FDA to consider it safe. The FDA may require companies to prove caffeine levels are safe if they exceed the guideline. Caffeine in energy drinks often ranges from 160 milligrams to 500 milligrams a serving, the FDA said in an August letter responding to Senator Durbin’s call for greater regulation of the industry.

Regulators are assessing the nation’s caffeine intake to ensure the amount in energy drinks is as safe as that in coffee, soda and tea, the FDA said earlier this year after Durbin raised the issue in April.

The parents of Fournier, the Maryland 14-year-old, are seeking damages in court in excess of $25,000, according to their complaint. The cause of the Dec. 23, 2011, death was “cardiac arrhythmia due to caffeine toxicity,” according to the lawsuit, which cited a state autopsy report. The Maryland medical examiner’s office in Baltimore said the autopsy cited is a valid report, without making any further comment about the legal claims related to the death.

A trial date hasn’t been set, the lawyer said. He said his firm, Goldberg, Finnegan & Mester in Silver Spring, Md., is investigating additional cases involving Monster and other energy drink companies.

“Our primary goal is to make sure Monster is aware of what Anais’ mother thinks the drink did to her child,” the lawyer, Goldberg, said in a telephone interview.

“It’s the first wrongful death case involving a minor child against an energy drink company that I’m aware of,” he said.